Process for treating metallic articles



Patented June 1931 UNITED STATES PATENT OFFICE OBIN A. BASSETT, OIOKLAHOMA CITY, OKLAHOMA, ASSIG NOB TO THE NATIONAL IN- DUSTRIALLABORATORIES CORPORATION, OF

POBATION OF DELAWARE OKLAHOMA CITY, OKLAHOMA, A COB- PROCESS FORTREATING METALLIC ARTICLES No Drawing. IApplication filed November Afteriron or steel has been coated with a metal of lower melting point, ithas heretofore been impossible to heat-treat the iron or steel withoutdestroying the coating. Tin or zinc coating on iron or steel has thusbeen narrowly confined to such articlesas could be coated as a finalstep and so leave the coating undisturbed. Correspondingly the advantageof a cheap anti-rust coating for steel has been verysharply limited.

In accordance with my invention, metals after being coated with othermetals which are inherently fugitive by-reason of relatively low meltingpoint or ready'oxidizability may be heat-treated variously as desiredwithout in any way damaging the coating. In some conditions, thecharacter of the coating may in fact be improved. Y

To the accomplishment of the foregoing and related ends, theinvention,then, consists of the features hereinafter fully described, andparticularly pointed out in the claims, the following'descriptionsetting forth but a few of the various ways in which the principle ofthe invention may be used.

In applying my process, I may proceed for example as follows :thearticle to be treated, for instance steel, is coated with a relativelylow melting metal such as zinc, by hot or by cold galvanizing, and isthen coated or covered by about to inch thick (depending upon the sizeof the article) with what for want of abetter name (and withoutcommitting myself to. any theory of action) I may call a fixative agent,and which comprises preferably a composition of potassium cyanide orsodium cyanide about 30 per cent, borax about 20 per cent, sodaash orsodium carbonate about 20 per cent., powdered carbon preferably graphiteabout 20 per cent. This may be applied dry where convenient by warmingthe steel article and plunging it into the powder so that enough willadhere,

or the material may be made up with an adhesive binder such as gluewater or the like and be spread on by a brush,.trowel or other con;venient means. The steel article is now heated up to the temperaturenecessary, and is quenched by water, oil or other means forthe temperingdesired, and on cleaning, the

6, 1925. Serial 1N0 67,453.

zinc coating will not only be'found intact, but capable of taking on asuperior polish. Instead of tempering, the steeLarticle canbe-annea-led, or the heating can be employed for the purpose of bendingor shaping the article. The feature in any case being the possibilityof, subjecting the metal-coated article to high temperatures for desiredheattreating or. shaping, temperatures which would normallylbedestructive to the metal coating, but w ich in accordance with myprocess are successfully borne. In this-mane ner tools, implements,cutlery, etc. can be galvanized or tinned and afterwards tem pered. Ican in fact make needles of tinned or galvanized iron wire and temperthem to any desired hardness.

The process is not confined to steel or to articles coated with zinc butmetal articles generally, coated with tin,- copper, brass, lead, etc.may be similarly successfully heat-treat ed without destroying themetal-coating Thus, not only steel but other iron-base articles canbetreated, for instance iron wire may be galvanized and then treated inaccordance with this process, the wire being coated with the fixativeagent and thensubjected to a cherry-red heat for a few minutes In thismanner wire and cables can be readily provided which will have thedesired tensile strength, hardness and'malleability and be thoroughlyrust-resisting for fencing, suspension bridge work, rigging, etc.

I may also take tinned or galvanized sheet iron barrels or barrel stockand coat withthe fixative and heat, and thus secure improvedrust-resisting and wearing barrels, cans, etc. By coating thin ironplates with the fixa tive and heating, then welding a number of theplates together, placing galvanized plates on the outside, superiorbuilt-up plate metal for, safes -armor plate, etc. may be produced.

Other modes of applying the principle of my invention may be employedinstead of the one explained, changes being made as regards themethodand means herein disclosed, provided the step or steps or means statedby any of the following claims or the equivalent of such stated step orsteps or means be em ployed.

I therefore particularly pomt out and distinctlX claim as my inventionprocess of treating metal coated with i a more fugitive metal, whichcomprises heating the coated metal in the presence of a fixative agentincluding the element carbon.

2. A process of treating metal coated with a more fugitive metal, whichcomprises heating the coated metal in the presence of a fixative agentincluding a cyanide.

3. A process of the character described, which comprises applying afixative agent including the element carbon to an iron-base articlecoated with a fugitive metal, and then heating.

4:. A process of the character described, which comprises a plying acyanide and free carbon to an ironase article coated with a fugitivemetal, and heating.

'5. A process of the character described, which comprises heating in thepresence of a cyanide and gra hite an iron-base article coated with afugitive metal.

6. A process of treating metal coated with a more fugitive metal,which'comprises applying a cyanide to the coated metal, and thenheating.

7. A process of treating me'tal coated with a more fugitive metal, whichcomprises aplying a fixative agent including a cyanide,

orax, sodiumcarbonate and carbon, to the coated metal, and then heating.

8. A process of treating metal coated with a more fugitive metal, whichcomprises a giying a fixative agent including a cyam' e,

rax, sodium carbonate and graphite, to the -coatedmetal, and thenheating. 9. A process of treating an iron-base arti-- cle coated with afugitive metal, which comprises applying a fixative agent including a Icyanide, borax, sodium carbonate and graphite, the coated metal,heating, and temper- 1n Y e 19signed by me .this 2nd day of November,

ORIN A. BASSETT.

